In this work newly derived non-local ionization coefficients covering the required high field range have been used, together with a random path length model, to accurately evaluate multiplication and excess noise in both InP and InAlAs multiplication regions. The multiplication of both the intentionally injected photocurrent and the tunneling current has been modeled. A range of APD multiplication widths have been evaluated and APD performance has been combined with a modeled receiver front end, to interpret the results in terms of receiver sensitivity.